QPR manager Harry Redknapp made no secret of his desire to strengthen the Rs squad during the January transfer window and Tal Ben Haim, Loic Remy, Yun Suk-young, Christopher Samba, Andros Townsend and Jermaine Jenas all arrived at Loftus Road.
Remy is set to miss the Liberty Stadium meeting with a groin problem, but even without the France striker it will be a very different QPR side from that thumped 5-0 by the Swans on the opening day of the season.
And with Redknapp's men desperate to improve their perilous position six points adrift of safety at the foot of the table, Williams knows they will pose a test.
"With a new manager and a team made up of a lot of new players, you don't really know what's going to happen. That's a fact," said the Wales captain.
"We went out and won that game against them on the opening day and that gave us a lot of confidence.
"But that was such a strange day and a lot has happened since then.
"Having said that, we feel like we can win most games these days, especially at home.
"We lost last Saturday at West Ham so we want to get back on track this week."